This study is designed to research the natural history of neurodevelopment, health and early hormonal function in infants with XXY/Klinefelter syndrome, XYY, XXX and other sex chromosome variations in an effort to identify early predictors of developmental and health outcomes. The Investigators will also evaluate different developmental screening tools in infants with sex chromosome variations so the investigators can develop recommendations for pediatrician caring for infants and young children with XXY/Klinefelter syndrome, XYY, XXX, and other sex chromosome variations.
Prenatal diagnosis of sex chromosome aneuploidy (by cfDNA, chorionic villi sampling, and/or amniocentesis)
Postnatal confirmatory karyotype of XXY, XYY, XXX, XXYY, XYYY, XXXY, XXXX, XXXXX, XXXXY, XXXYY, XXYYY, XYYYY (including any mosaicism with <80% 46,XX or 46,XY cell line)
English or Spanish speaking
Age 6 weeks to 12 months 30 days on enrollment
Previous diagnosis of a different genetic or metabolic disorder with neurodevelopmental or endocrine involvement
Prematurity less than 34 weeks gestational age
Complex congenital malformation not previously associated with sex chromosome aneuploidy
History of significant neonatal complications (ie intraventricular hemorrhage, meningitis, hypoxic-ischemic encephalopathy)
Sex Chromosome Trisomies (SCT) including Klinefelter (XXY), Trisomy X (XXX), and XYY. Rare sex tetrasomy and pentasomy conditions are also eligible.
Case-only
Prospective
Assessments of Development and Growth
Other interventionLongitudinal observational assessments of development and growth at ages: 2 months, 6 months, 12 months, 18 months, 24 months, 36 months, 48 months, 5 years, 6 years, 7 years, 8 years, 9 years of age.
Longitudinal Descriptive Statistics of Cognitive Scores on the Bayley-III
Cognitive skills will be assessed using the standardized Bayley Scales of Infant Development--3rd Edition (Bayley-3)
Longitudinal Descriptive Statistics of Motor Scores on the Bayley-III
Motor development will be assessed using the standardized Bayley Scales of Infant Development--3rd Edition (Bayley-3)
Longitudinal Descriptive Statistics of Language Scores on Bayley-III
Language development will be assessed using the Bayley Scales of Infant Development--3rd Edition (Bayley-3)
Body Mass Index (BMI)
BMI will be determined through measurement of length and weight at the research visit.
Z Score
The z score will be calculated for age group at the research visit.
Body Composition (% body fat)
Body fat percentage will be measured using air Dual Energy X-Ray Absorptiometry (DEXA) at 3 year old visit.
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